arch/powerpc/kernel/dma.c

   1 /*
   2  * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
   3  *
   4  * Provide default implementations of the DMA mapping callbacks for
   5  * directly mapped busses.
   6  */
   7
   8 #include <linux/device.h>
   9 #include <linux/dma-mapping.h>
  10 #include <linux/dma-debug.h>
  11 #include <linux/gfp.h>
  12 #include <linux/memblock.h>
  13 #include <linux/export.h>
  14 #include <asm/bug.h>
  15 #include <asm/abs_addr.h>
  16 #include <asm/machdep.h>
  17
  18 /*
  19  * Generic direct DMA implementation
  20  *
  21  * This implementation supports a per-device offset that can be applied if
  22  * the address at which memory is visible to devices is not 0. Platform code
  23  * can set archdata.dma_data to an unsigned long holding the offset. By
  24  * default the offset is PCI_DRAM_OFFSET.
  25  */
  26
  27
  28 void *dma_direct_alloc_coherent(struct device *dev, size_t size,
  29                                 dma_addr_t *dma_handle, gfp_t flag)
  30 {
  31         void *ret;
  32 #ifdef CONFIG_NOT_COHERENT_CACHE
  33         ret = __dma_alloc_coherent(dev, size, dma_handle, flag);
  34         if (ret == NULL)
  35                 return NULL;
  36         *dma_handle += get_dma_offset(dev);
  37         return ret;
  38 #else
  39         struct page *page;
  40         int node = dev_to_node(dev);
  41
  42         /* ignore region specifiers */
  43         flag  &= ~(__GFP_HIGHMEM);
  44
  45         page = alloc_pages_node(node, flag, get_order(size));
  46         if (page == NULL)
  47                 return NULL;
  48         ret = page_address(page);
  49         memset(ret, 0, size);
  50         *dma_handle = virt_to_abs(ret) + get_dma_offset(dev);
  51
  52         return ret;
  53 #endif
  54 }
  55
  56 void dma_direct_free_coherent(struct device *dev, size_t size,
  57                               void *vaddr, dma_addr_t dma_handle)
  58 {
  59 #ifdef CONFIG_NOT_COHERENT_CACHE
  60         __dma_free_coherent(size, vaddr);
  61 #else
  62         free_pages((unsigned long)vaddr, get_order(size));
  63 #endif
  64 }
  65
  66 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
  67                              int nents, enum dma_data_direction direction,
  68                              struct dma_attrs *attrs)
  69 {
  70         struct scatterlist *sg;
  71         int i;
  72
  73         for_each_sg(sgl, sg, nents, i) {
  74                 sg->dma_address = sg_phys(sg) + get_dma_offset(dev);
  75                 sg->dma_length = sg->length;
  76                 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
  77         }
  78
  79         return nents;
  80 }
  81
  82 static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
  83                                 int nents, enum dma_data_direction direction,
  84                                 struct dma_attrs *attrs)
  85 {
  86 }
  87
  88 static int dma_direct_dma_supported(struct device *dev, u64 mask)
  89 {
  90 #ifdef CONFIG_PPC64
  91         /* Could be improved so platforms can set the limit in case
  92          * they have limited DMA windows
  93          */
  94         return mask >= get_dma_offset(dev) + (memblock_end_of_DRAM() - 1);
  95 #else
  96         return 1;
  97 #endif
  98 }
  99
 100 static u64 dma_direct_get_required_mask(struct device *dev)
 101 {
 102         u64 end, mask;
 103
 104         end = memblock_end_of_DRAM() + get_dma_offset(dev);
 105
 106         mask = 1ULL << (fls64(end) - 1);
 107         mask += mask - 1;
 108
 109         return mask;
 110 }
 111
 112 static inline dma_addr_t dma_direct_map_page(struct device *dev,
 113                                              struct page *page,
 114                                              unsigned long offset,
 115                                              size_t size,
 116                                              enum dma_data_direction dir,
 117                                              struct dma_attrs *attrs)
 118 {
 119         BUG_ON(dir == DMA_NONE);
 120         __dma_sync_page(page, offset, size, dir);
 121         return page_to_phys(page) + offset + get_dma_offset(dev);
 122 }
 123
 124 static inline void dma_direct_unmap_page(struct device *dev,
 125                                          dma_addr_t dma_address,
 126                                          size_t size,
 127                                          enum dma_data_direction direction,
 128                                          struct dma_attrs *attrs)
 129 {
 130 }
 131
 132 #ifdef CONFIG_NOT_COHERENT_CACHE
 133 static inline void dma_direct_sync_sg(struct device *dev,
 134                 struct scatterlist *sgl, int nents,
 135                 enum dma_data_direction direction)
 136 {
 137         struct scatterlist *sg;
 138         int i;
 139
 140         for_each_sg(sgl, sg, nents, i)
 141                 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
 142 }
 143
 144 static inline void dma_direct_sync_single(struct device *dev,
 145                                           dma_addr_t dma_handle, size_t size,
 146                                           enum dma_data_direction direction)
 147 {
 148         __dma_sync(bus_to_virt(dma_handle), size, direction);
 149 }
 150 #endif
 151
 152 struct dma_map_ops dma_direct_ops = {
 153         .alloc_coherent                 = dma_direct_alloc_coherent,
 154         .free_coherent                  = dma_direct_free_coherent,
 155         .map_sg                         = dma_direct_map_sg,
 156         .unmap_sg                       = dma_direct_unmap_sg,
 157         .dma_supported                  = dma_direct_dma_supported,
 158         .map_page                       = dma_direct_map_page,
 159         .unmap_page                     = dma_direct_unmap_page,
 160         .get_required_mask              = dma_direct_get_required_mask,
 161 #ifdef CONFIG_NOT_COHERENT_CACHE
 162         .sync_single_for_cpu            = dma_direct_sync_single,
 163         .sync_single_for_device         = dma_direct_sync_single,
 164         .sync_sg_for_cpu                = dma_direct_sync_sg,
 165         .sync_sg_for_device             = dma_direct_sync_sg,
 166 #endif
 167 };
 168 EXPORT_SYMBOL(dma_direct_ops);
 169
 170 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 171
 172 int dma_set_mask(struct device *dev, u64 dma_mask)
 173 {
 174         struct dma_map_ops *dma_ops = get_dma_ops(dev);
 175
 176         if (ppc_md.dma_set_mask)
 177                 return ppc_md.dma_set_mask(dev, dma_mask);
 178         if ((dma_ops != NULL) && (dma_ops->set_dma_mask != NULL))
 179                 return dma_ops->set_dma_mask(dev, dma_mask);
 180         if (!dev->dma_mask || !dma_supported(dev, dma_mask))
 181                 return -EIO;
 182         *dev->dma_mask = dma_mask;
 183         return 0;
 184 }
 185 EXPORT_SYMBOL(dma_set_mask);
 186
 187 u64 dma_get_required_mask(struct device *dev)
 188 {
 189         struct dma_map_ops *dma_ops = get_dma_ops(dev);
 190
 191         if (ppc_md.dma_get_required_mask)
 192                 return ppc_md.dma_get_required_mask(dev);
 193
 194         if (unlikely(dma_ops == NULL))
 195                 return 0;
 196
 197         if (dma_ops->get_required_mask)
 198                 return dma_ops->get_required_mask(dev);
 199
 200         return DMA_BIT_MASK(8 * sizeof(dma_addr_t));
 201 }
 202 EXPORT_SYMBOL_GPL(dma_get_required_mask);
 203
 204 static int __init dma_init(void)
 205 {
 206        dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 207
 208        return 0;
 209 }
 210 fs_initcall(dma_init);
 211
 212 int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
 213                       void *cpu_addr, dma_addr_t handle, size_t size)
 214 {
 215         unsigned long pfn;
 216
 217 #ifdef CONFIG_NOT_COHERENT_CACHE
 218         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 219         pfn = __dma_get_coherent_pfn((unsigned long)cpu_addr);
 220 #else
 221         pfn = page_to_pfn(virt_to_page(cpu_addr));
 222 #endif
 223         return remap_pfn_range(vma, vma->vm_start,
 224                                pfn + vma->vm_pgoff,
 225                                vma->vm_end - vma->vm_start,
 226                                vma->vm_page_prot);
 227 }
 228 EXPORT_SYMBOL_GPL(dma_mmap_coherent);